What are the pros & cons of fiberglass replacement windows?

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Keeping the Kansas City elements out is one of the primary jobs of your home’s windows, and if you have been considering upgrading your windows you may be wondering how fiberglass replacement windows stack up to other materials like wood and vinyl.

We’re going to take a close look at what exactly fiberglass is and how fiberglass windows are made. Then we’ll dive into a list of pros and cons, so you know how fiberglass windows are going to compare to your existing windows and other potential replacement window materials.

What Are Fiberglass Windows

Fiberglass windows are made from the same material as boats, jet skis, and even some car body components. It is a super tough and durable material made by weaving glass fibers into a resin, then hardening that composition into the shape of the final material or component. With windows, the frames and window surrounds are fiberglass, which makes the window itself considerably tougher than materials like vinyl or wood.

The Pros & Cons Of Fiberglass Replacement Windows



Fiberglass is an incredibly strong material that can stand up to a lot of Kansas City weather. Fiberglass can stand up to heat, cold, water, ice, and even the occasional hail storm. It is the same material that many boat hulls are made out of, so you know it can take a beating without failure.

Energy Efficiency

Fiberglass is considered a powerful insulator and as such, fiberglass windows provide a considerable boost to the overall energy efficiency of the home, as well as making it more comfortable and livable. This bump in efficiency comes with several benefits to the homeowner.

Higher energy efficiency means that your home’s HVAC equipment doesn’t have to work as hard to do the same job. The windows help keep the cold out in the winter, and the heat out in the summer. This cuts down on energy bills, saving the homeowner money, but it also puts less stress on the HVAC components, which lowers the long-term costs of maintenance and repairs.

Customization Potential

Many homeowners choose fiberglass windows because they can be painted on the interior of the home. This means that they can be blended in with existing decor and color schemes, without affecting the exterior appearance at all. This is much different than vinyl windows, for example, which must be color-matched ahead of time and cannot be successfully painted at all.


It’s A Painted Material

Fiberglass windows come from the factory already painted, and that paint job is one of the best parts of fiberglass windows, but it comes with a life expectancy. This life expectancy is often about 6-8 years, from the factory, after which, the windows will begin to show obvious signs of wear.

They will begin fading, scuffing, and generally displaying a diminished appearance. Most fiberglass window companies do provide a warranty that will cover repainting if the conditions are met, but it can be a considerable hassle to have a painting crew come to your home to paint your windows.

Warranty Painting Is Not Very Strong

When fiberglass windows are first made, they are given robust primer coats as well as coats of paint that are baked on to harden them against the elements. This is the finish that is given the initial warranty by the manufacturer but remember that the warranty is going to be less than 10 years and to repaint, you’ll have a fiberglass painting crew come out to your home.

This means, however, that while you may be getting a paint job covered by the warranty, it’s also a paint job that occurs on-site. They will have conventional paint sprayers or other application methods, but the final paint finish will not be baked-on as it is in the factory. This leads to a constantly shrinking length of time that fiberglass windows look nice, following a painting.

For More Information About Fiberglass Windows

Fiberglass windows can be a great option for your window upgrade project, but as you’ve seen, there are situations where the drawbacks of fiberglass may be too much. For more information about fiberglass replacement windows, contact Thermal King today and talk with a trusted member of our window installation team.